Date: Sun, 17 Sep 2000 09:48:57 -0500 Reply-To: Maryland Birds & Birding Sender: Maryland Birds & Birding From: rick Subject: Re: Eared Grebes in Maryland Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" I want to endorse Marshall's note about the probability that Eared Grebes are more likely (and more likely overlooked) in Maryland than Horneds from late August through early October. The growing body of evidence from the East strongly supports his argument. There is another factor that should be taken into consideration. Although precise evidence is very hard to come by, what little that is available suggests that any bird in full winter plumage in September is much more likely to be an Eared. It is nearly impossible to find any information about molts of grebes in North America and what there is is anecdotal and sometimes contradictory. Still, on the basis of what there is, it seems likely that Eared Grebes molt about a month earlier than Horneds. That is probably related to their earlier migration because both species largely finish their molts before moving significant distances in the fall and every source that has information indicates that Eared Grebes are on the move about a month earlier than Horneds. The only sources in which I found data on molts were from Europe and there might be differences between Old World and New World birds, although the limited evidence suggests that they are similar. I have seen only a few Horned Grebes in September (not in Maaryland), and all showed clear evidence of retained breeding plumage, although they were in molt. When I lived in California I rarely saw any Eared Grebes with retained breeding plumage in September. I would go so far as to suggest that any small (nonPied-billed) grebe seen in Maryland before the second week in October should be assumed to be an Eared unless proven otherwise and that if it is in full winter/juvenile plumage, the assumption should be even stronger. I would also be interested in hearing about other people's experience with late August-September Horned Grebes, especially impressions about plumage and I am still looking for published information about the precise timing of molt in North American birds. I will quibble a bit with Marshall's contention about Horned Grebes not appearing inland as frequently. In general I suspect that he is right but I would not go too far out on the limb on this one. I have seen a lot of Horned Grebes inland in the fall (well, I mostly bird inland). I have even seen them on smallish ponds and in sewage lagoons, but I think they are the exception rather than the rule. My gut reaction, based entirely on my own experience and no reading on the subject, is that water depth may be a key. Most of the Horned Grebes I have seen inland have been in deeper ponds and lakes, such as Piney Run. The Eared Grebes I have seen, while they have been on both largish and small ponds and lakes, seem to favor shallower water than Horneds, even when they occur together. None of this is written in stone, however and where an individual ends up may depend on what was available when the bird had to get out of the sky. Still, I have seem Eared Grebes persistently feeding by diving in water I could walk around in in knee boots and I don't ever remember seeing a Horned Grebe doing that. Rick I love deadlines. I like the whooshing sound they make as they fly by. - Douglas Adams Rick Blom rblom@blazie.com 4318 Cowan Place Belcamp, Maryland 21017 (410)575-6086 Editor: BWD Skimmer (www.birdwatchersdigest.com) ======================================================================= To leave the MDOsprey list, send e-mail to listserv@home.ease.lsoft.com with the following message in line 1: signoff mdosprey ======================================================================= =========================================================================